/*=====================================================================*
 *                   Copyright (C) 2011 Paul Mineiro                   *
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#ifndef __DYADICP_HH__
#define __DYADICP_HH__

#include <utility>

namespace flassol
{
  namespace dyadic
    {
      // Given a p, find an s such that
      //
      // p == adotb * cosh (2 * s) 
      //      - anormplusbnorm cosh (s) sinh (s) 
      //      + wdotx - s xnorm
      //      - onedotone       
      //
      // The first element of the pair is a flag which indicates
      // whether or not catastrophic cancellation has been detected

      std::pair<bool, float>
      pinv (float p,
            float adotb,
            float anormplusbnorm,
            float wdotx,
            float xnorm,
            float onedotone);

      // This is the forward function, but implemented to 
      // avoid catastrophic cancellation as much as possible.
      //
      // p == adotb * cosh (2 * s) 
      //      - anormplusbnorm cosh (s) sinh (s) 
      //      + wdotx - s xnorm
      //      - onedotone       
      //
      // The first element of the pair is a flag which indicates
      // whether or not catastrophic cancellation has been detected

      std::pair<bool, float>
      p (float s,
         float adotb,
         float anormplusbnorm,
         float wdotx,
         float xnorm,
         float onedotone);
    }
}

#endif // __DYADICP_HH__
